From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 08841171B5 for ; Thu, 2 Nov 2023 12:07:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="tBm5B3hT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 43E5EC433C8; Thu, 2 Nov 2023 12:07:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1698926861; bh=xSE58Aje/v66DeXgYWtNHYfh66tVbkIWO7Rg8XNcywo=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=tBm5B3hTGS4GZArwtuFrMD/sN7WSCmWjJHJLPCkd41R6u2M5sAXgAFpYNIdRTabEH 4mLPysXX912aTZQa5o0J1+MhZA0MNZY90D+t1bC5LdkEFma1iDlv6h11Vx7rPD4uCn mJ8XRqVbVebOshN+IvuXMoSV83q5aMvJeg31uSEoEnXS2B3kw19uo5MJw/cakHe07t odiyzoeXIPAN7t3KXeLcIUlDUefofkA4++ufUq4BK9936QgMXmaDi/zGcU1KALfMCQ hRnINZgfeNL5Sk5pD3C/QRM3ZZZsYmxUuyQfOYSrj0waEJ1hZR6S5ZeBSzM62OcjjI 6Ti6KTn4/O3+Q== Date: Thu, 2 Nov 2023 07:07:39 -0500 From: Bjorn Helgaas To: Mika Westerberg Cc: Mario Limonciello , bhelgaas@google.com, andreas.noever@gmail.com, michael.jamet@intel.com, YehezkelShB@gmail.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, Alexander.Deucher@amd.com Subject: Re: [PATCH 2/2] PCI: Ignore PCIe ports used for tunneling in pcie_bandwidth_available() Message-ID: <20231102120739.GA114661@bhelgaas> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231102103108.GK17433@black.fi.intel.com> On Thu, Nov 02, 2023 at 12:31:08PM +0200, Mika Westerberg wrote: > On Wed, Nov 01, 2023 at 08:14:31PM -0500, Mario Limonciello wrote: > > On 11/1/2023 17:52, Bjorn Helgaas wrote: > > > Lukas' brief intro in > > > https://lore.kernel.org/all/20230925141930.GA21033@wunner.de/ really > > > helped me connect a few dots, because things like > > > Documentation/admin-guide/thunderbolt.rst assume we already know those > > > details. > > > > Thanks for sharing that. If I move the detection mechanism as I suggested > > above I'll reference some of that as well in the commit message to explain > > what exactly a tunneled port is. > > I'm not sure it makes sense to explain from the zero all this stuff that > people can easily look up from the corresponding spec, such as PCIe or > USB. I don't know if it needs to be in the commit log. I mentioned thunderbolt.rst because the text at https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/admin-guide/thunderbolt.rst?id=v6.6#n6 assumes that we know the terms "host router", "host controller", "router", "tunnel", "connection manager", and I don't think that's a good assumption in that documentation. A little bit of introduction based on Lukas' text could improve that. > There is a good picture in USB4 v2 ch 2.2.3 about paths crossing USB4 > fabric, perhaps reference that one? Or ch 2.2.10.3 that shows how this > works with PCIe tunneling instead (although they are similar). Thanks for these! Bjorn